The objective of the proposed research is to continue to evaluate articular cartilage viability, metabolism, and mechanical properties following cartilage storage and joint resurfacing with preserved, viable cartilage. Rabbit, dog, and human in vitro articular cartilage models are to be characterized as to biosynthesis and catabolism of articular cartilage macromolecules, and as to the composition and type of collagen, collagen crosslinks, and glycosaminoglycans. The viscoelastic properties are to be determined by two different methods: 1) a new, sensitive test for determining the complex shear modulus and 2) cyclic indentation testing. Methods to be utilized include uptake and release of several different labeled amino acids; the extraction and solubilization, fractional precipitation, ion exchange chromatography, gel filtration, cyanogen bromide cleavage, polyacrylamide disc gel electrophoresis, pepsin digestion as an enzymatic probe to determine the thermal denaturation of newly synthesized collagen; and mechanical testing using the CGS/Lawrence Dynamic Tensile Testing Machine. Articular cartilage slices, plugs, and whole condyles are to be stored at 37 degrees C in modified tissue culture medium, and then tested mechanically and biochemically utilizing the above methods. Denuded dog femoral condyles are to be resurfaced with preserved, viable osteochondral shells, and viability, metabolism, and mechanical properties following transplantation are to be evaluated by the methods above.